This week in the woods, we see an array of tree seeds splayed across the snow that reflect the composition of our forests.
This hophornbeam bract separated from a conelike cluster that made up a female flower. The “strobiles” the bracts come from resemble the hops used in brewing beer and give the tree its name. Each flattish, papery, bladder-like sac contains a nutlet.
A gray birch cone scale looks different from other birch species’ cone scales for its backward curved lobes. During the fall and winter, the wind disperses these minute, three-lobed, hardened structures. “The seeds are tiny and light and are often blown such a great distance from the parent tree that the source of the seed seems mysterious,” writes Virginia Barlow in an article from our archives. “Long ago, when thickets of gray birch sprang up in abandoned fields or burnt-over land, some people thought that the tree had managed to reproduce spontaneously – without any seeds.”
If gray birch cone scales resemble gliding birds, yellow birch cone scales (which we wrote about last year) look like little bird feet. Yellow birch cones release their seeds slowly, meaning that the scales scatter across the top of the snow deeper into the year and serve as a vital late-winter food source.
Ruffed grouse take advantage of the late availability of sustenance from yellow birch, as they do of pre-formed buds, nuts, and catkins of hophornbeam, the buds and male catkins of gray birch, and many other trees. Once the fall crops of fruit and nuts have been largely eaten or buried by snow, they switch to a winter diet largely of buds and twigs “pruned” from trees and, toward the end of the winter, staghorn sumac seeds. Overwintering success depends most heavily on aspens, with which ruffed grouse have the strongest association. Male aspen catkins offer exceptionally high energy density and cluster on stout, sturdy branches easy to perch and feed upon. In the low-light morning and evening hours, ruffed grouse can fill their crops efficiently in these trees, retreat to their snow caves or canopy roosts, and digest out of predators’ view. As early- and mid-successional forests have matured in the Northeast, ruffed grouse populations have declined. Quaking and big-tooth aspens – pioneer species with max lifespans of about 70 years – die out, and the dense undergrowth grouse prefer for cover is also reduced. In older forests, grouse favor yellow birch, but these trees have only small clusters of buds and catkins on flimsy branches, which necessitates more predator-attracting movement and noise in exchange for less nutrition. The ever-popular quaking aspen buds, shown here, have a glossy, dark brown color and are pointy and incurved.
Also out there in the woods year-round: greenshield lichen (this one most likely common greenshield lichen, found growing on spruce bark in this case). The light yellow-green lichen grows in what Rachel Sargent Mirus calls “doily-like blotches” and has fat, rounded lobes and more wrinkles in its older portions. Hummingbirds prefer foliose (“leafy”) lichens like greenshield for their nests, as the little slender-billed birds can easily pluck the more loosely attached outer edges.
What have you noticed in the woods this week? Submit a recent photo for possible inclusion in our monthly online Reader Photo Gallery.